fastpdf2png 1.0.0

Ultra-fast PDF to PNG converter

fastpdf2png

Fast PDF to PNG converter. SIMD-optimized PNG encoding, automatic grayscale detection, multi-process scaling. MIT licensed.

Install

pip install fastpdf2png

Or build from source:

git clone https://github.com/nataell95/fastpdf2png.git && cd fastpdf2png
bash scripts/build.sh

Usage

CLI

./build/fastpdf2png input.pdf page_%03d.png 300 4 -c 2

Python

import fastpdf2png

images = fastpdf2png.to_images("doc.pdf")        # list of PIL images
fastpdf2png.to_files("doc.pdf", "output/")        # save PNGs to disk
data   = fastpdf2png.to_bytes("doc.pdf")          # raw PNG bytes
n      = fastpdf2png.page_count("doc.pdf")        # page count

# Batch processing — keep PDFium loaded between calls
with fastpdf2png.Engine() as pdf:
    for path in my_pdfs:
        images = pdf.to_images(path, dpi=150)

Node.js

const pdf = require("fastpdf2png");

pdf.toFiles("doc.pdf", "output/", { dpi: 150 });
const buffers = pdf.toBuffers("doc.pdf");
const count = pdf.pageCount("doc.pdf");

// Batch processing
const engine = new pdf.Engine();
await engine.toFiles("doc.pdf", "output/");
engine.close();

Performance

71-page PDF (mixed: text, charts, tables, images) on Apple M3 Max. All tools single-process, compression level 2.

Engine	72 DPI	150 DPI	300 DPI	File size
fastpdf2png	531 pg/s	323 pg/s	145 pg/s	-38%
MuPDF	119	37	12	baseline
PyMuPDF	101	30	9	baseline

With multiple workers (150 DPI):

Workers	Pages/sec
1	323
2	582
4	985
8	1536

How it works

PDFium renders pages to BGRA bitmaps. A SIMD pass (NEON/AVX2) checks if R==G==B — if so, the page is encoded as 8-bit grayscale (1/3 the data). A patched libdeflate compresses into a single IDAT chunk, assembled zero-copy into a valid PNG. Workers run as fork() processes with shared-memory atomic page counters.

CLI reference

fastpdf2png <input.pdf> <output_%03d.png> [dpi] [workers] [-c level]
fastpdf2png --info <input.pdf>
fastpdf2png --daemon

Flag	Default	Description
dpi	300	Output resolution
workers	1	Parallel processes
-c 0/1/2	0	Compression: fast / medium / best
--info		Print page count
--daemon		Persistent mode (stdin commands)

Platforms

OS	Arch	SIMD
macOS	arm64	NEON
macOS	x86_64	AVX2, SSE4.1
Linux	x86_64	AVX2, SSE4.1
Linux	arm64	NEON

License

MIT. See LICENSE and THIRD_PARTY_LICENSES.md.

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_{Built for Miruiq — AI-powered data extraction from PDFs and documents.}